Double-hulled boats

ABSTRACT

A double-hulled boat with flotation material is disclosed. An inner hull constitutes a complete floatable shell and has integrally formed bottom, side and end walls with a flange extending laterally outwardly at the upper edges of the side walls. The outer hull is similarly integrally formed and has a bottom, side and end walls, the side walls having a flange of smaller lateral dimensions than the inner hull so that the flanges are nestably mating and can be bonded together to define a flotation material-containing cavity therebetween. In the method of the invention the flotation material is sprayed on the exterior side walls of the inner hull before assembly. The inner and outer hulls are made of fiberglass. A plywood inner floor is sandwiched between the bottoms of the inner and outer hulls with a keel and skeletal rib structure disposed beneath the inner floor. The bottom of the outer hull is shaped to receive and retain the keel and rib structure. The keel, rib structure, inner floor and bottom portions of the two hulls are bonded and cured together as are the flanges to form a water-tight, buoyant and durable structure.

United States Patent [191 Moore et al.

[ Aug. 27, 1974 1 DOUBLE-HULLED BOATS [76] Inventors: Richard L. Moore; Vaughn Moore;

Warren N. Moore, all of Highway 80, East Bossier City, La. 71010 [22] Filed: Aug. 3, 1973 [21] Appl. No.: 385,272

[52] US. Cl 9/6, 114/63, 114/65 R [51] Int. Cl 1363b 5/24 [58] Field of Search 9/6, 6.5; 114/56, 62, 63, 114/65 R [56] References Cited UNITED STATES PATENTS 2,376,753 5/1945 Bowen 9/6 2,866,985 1/1959 Blackmore 9/6 3,063,069 1 1/1962 Briimmer 9/6 3,126,856 3/1964 Fuller 9/6 X 3,315,284 4/1967 Ludlow 9/6. 3,372,408 3/1968 Luger et a1. 9/6

Primary Examiner-Lloyd L. King Assistant Examiner-Randolph A. Reese Attorney, Agent, or Firm-Roylance, Abrams, Berdo & Kaul ABSTRACT A double-hulled boat with flotation material is disclosed. An inner hull constitutes a complete floatable shell and has integrally formed bottom, side and end walls with a flange extending laterally outwardly at the upper edges of the side walls. The outer hull is similarly integrally formed and has a bottom, side and end walls, the side walls having a flange of smaller lateral dimensions than the inner hull so that the flanges are nestably mating and can be bonded together to define a flotation materiabcontaining cavity therebetween. 1n the method of the invention the flotation material is sprayed on the exterior side walls of the inner hull be fore assembly. The inner and outer bulls are made of fiberglass. A plywood inner floor is sandwiched between the bottoms of the inner and outer hulls with a keel and skeletal rib structure disposed beneath the inner floor. The bottom of the outer hull is shaped to receive and retain the keel and rib structure. The keel, rib structure, inner floor and bottom portions of the two hulls are bonded and cured together as are the flanges to form a water-tight, buoyant and durable structure.

2 Claims, 3 Drawing Figures DOUBLE-HULLED BOATS This invention relates to an improved method and apparatus for constructing a small boat, specifically a double-hulled boat having flotation material encased therein.

Relative recent safety requirements and construction techniques have stimulated considerable activity in the field of small boat construction, primarily of boats intended for leisure and fishing use and of a type useable with or without an outboard motor. Various relatively complicated construction techniques have been developed for manufacturing such boats, but all such known techniques are expensive or complicated and therefore add to the price of the ultimate product.

Accordingly, it is an object of the present invention to provide an economically producable novel structure of improved characteristics for a small boat, the structure being of the double-hulled variety.

A further object is to provide a double-hulled small boat having a substantial quantity of flotation material properly disposed to maintain the boat in an upright condition.

Yet another object is to provide a double-hulled boat in which the two hulls are independently flotable and integrally formed and thereafter bonded together.

A further object is to provide a method of manufacturing a double-hulled boat in which two independently floatable integrally formed hulls are provided, the inner one being shaped to define a cavity with the other one when assembled, the inner one being provided with an exterior layer of flotation material at the portion where the cavity will exist, the two hulls being assembled after application of the foam and bonded together with skeletal keel and rib structures to form a rigid, durable craft.

Broadly described, the structure of the boat includes an inner hull which is integrally formed to have a flat bottom and upstanding side and end walls and a peripheral flange protruding outwardly from at least the side walls and having an upstanding outer edge. An outer hull is produced with a somewhat similar flange but having a shorter lateral dimension, the flanges being formed and dimensioned to mate when the two hulls are joined together. The inner hull flange is dimensioned to define, with the side walls and the bottom of the outer hull, a cavity which is substantially totally filled with a flotation material. An inner floor is disposed between the inner and outer hulls and a keel and rib structure is fitted into the bottom of the outer hull before assembly, covered with the inner floor, to provide rigidity and additional strength. The various contacting portions of the inner and outer hulls, floor and rib structure are securely bonded and cured to provide a sound, water-tight ultimate product.

The method of the invention involves forming the inner and outer hulls independently so that each is a separately floatable integrally formed hull but with mating flange portions around the upper edges thereof; applying a layer of flotation material between the exterior surface of the inner hull and the interior surface of the outer hull except where the inner hull is to mate with the outer hull or the support structure; providing cavities in the bottom portion of the outer hull to re ceive a keel member and a plurality of transverse ribs; assembling the components by placing the keel and rib structure in the outer hull, covering same with the inner floor, inserting the inner hull to which the flotation material has previously been applied, and bonding the inner and outer hulls together at the flange and the inner hull to the inner floor and rib structure which is also bonded to the outer hull.

In order that the manner in which the foregoing and other objects are attained in accordance with the invention can be understood in detail, a particularly advantageous embodiment will be described with reference to the accompanying drawings, which form a part of this specification, and wherein:

PK]. 1 is a transverse section of an assembled craft in accordance with the invention;

FIG. 2 is an exploded transverse sectional view of the craft of FIG. 1; and

FIG. 3 is a longitudinal section along lines 3-3 of FIG. 1.

Referring now to the drawings in detail, it will be seen that the boat of the present invention includes an inner hull indicated generally at 10, an outer hull indicated generally at 11, flotation material. 12 and 13, an inner floor 14, a keel member 15, and a plurality of transverse ribs 16.

The inner hull includes a bottom portion 20 which is substantially flat but which curves upwardly in accordance with the general principles of small boat design, to form whatever kind of prow is desired. As will be seen, the specific design chosen for illustration in FIGS. l-3 has a relatively blunt forward end so that the bottom portion curves into and becomes a forward wall 21. Various other well known boat designs can, of course, be employed in accordance with the principles of the present invention.

The inner hull also includes upstanding side walls 22 and 23 which are integrally formed with the bottom and front walls. A rear end wall or transom 24 is also integrally formed with the bottom and side walls and extends upwardly, terminating in a common plane with the walls 2123.

Side wall 22 is smoothly contoured into and integrally formed with a laterally outwardly extending flange 26 which is substantially parallel to bottom portion 20. Wall 23 similarly is integrally formed with a lat erally outwardly extending flange 27 which is parallel to flange 26 and bottom 20. Flanges 26 and 27 terminate in integrally formed upwardly extending relatively short wall portions. constituting the upper limit of the wall structure in each case. It will be observed that end walls 21 and 24 are not provided with similar flanges, but could be if desired from the point of view of structural strength, esthetics or water-tight integrity.

An important aspect of the inner hull structure is the fact that it constitutes, independently, a fully watertight, integrally formed independently floatable hull. [t can be made of any suitable boat construction material such as reinforced fiberglass or the like.

The outer hull 11 includes a bottom portion having a somewhat more complicated shape than the inner hull and includes a central downwardly extending longitudinal cavity 30 which is designed to receive the longitudinal keel member 15. Substantially flat. but slightly angled bottom portions 31 and 32 extend transversely outwardly from recess 30 and form the major portion of the outer hull and the boat bottom. At the lateral limits of portions 31 and 32 are relatively short upwardly extending walls 34 and 35 which are integrally formed with the side walls 40 and 41 of the hull structure.

In a manner similar to the inner hull structure, wall 40 smoothly merges with a relatively short laterally outwardly extending integrally formed flange 42 which is provided at its outer edge with an upstanding relatively short wall 43. Similarly, the upper portion of side wall 41 is formed with a laterally outwardly extending flange 44 which has an upwardly extending short wall 45. It will be observed that the inner surfaces of walls 43 and 45 are dimensioned to receive and be of substantially the same height as walls 28 and 29 of the inner hull structure so that those portions of the inner and outer hulls mate in a nesting relationship. However, the flanges from the inner hull are substantially wider than the outer hull flanges so that interhull cavities are defined between side walls 22 and 40 and 23 and, respectively, in the assembled relationship.

Front and rear end walls 48 and 49, respectively, complete the outer hull structure.

The cavities thus defined contain flotation material 12 and 13. This material can be of any conventional sprayable buoyant material of a foaming type which can be applied to the exterior of the inner hull before assembly. As will be seen, flanges 26 and 27 form the upper limits of the cavities and the lower limits thereof are defined by the portions of inner floor 14 which protrude beyond the outer portions of the inner hull. Floor 14 abuts the inner surfaces of walls 40 and 41 and is supported by the junctures of walls 34 and 37, on one side, and walls 35 and 38 on the other side. In the center the inner floor and the bottom portion 20 of the inner hull are supported by keel member 15 and between these longitudinal points of support the floor and bottom portions rest on rib members 16 which extend transversely at spaced points along the boat. As mentioned above, surfaces 31 and 32 are formed to exactly fit the under surfaces of the rib structures so that there is a close conformance and fit therebetween.

The method by which the boat is assembled begins with the formation, from fiberglass, or other suitable polymeric material, of the inner and outer hulls. These shells are formed to be assembled in pairs, depending upon the style boat desired, with the nestable mating flanges suitably dimensioned to conform to each other.

The rib and keel structure can then be placed in the bottom portion of the outer hull with a suitable bonding adhesive material therebetween in an uncured state. These components are pressed together and the bonding material is then cured. A typical bonding material suitable for this purpose is a fiberglass resin, but any waterproof adhesive or bonding material having adequate strength characteristics and compatability with the hull and support materials can be used. The bonding material is then placed on top of the keel and rib structure and the inner floor is placed thereon, this inner floor serving to seal the keel and rib compartments from the upper portions of the boat by close conformance of the periphory thereof to the interior of the outer hull.

The flotation material is then sprayed or otherwise adhered to the outer surface of the inner hull in a layer of sufficient thickness to substantially totally fill the void which will be created in assembly of the craft.

The foam can also be sprayed on the inner surface of the outer hull. The foam is of a type which foams in about 5-7 seconds, forms a stiff, relatively rigid layer in about 30 seconds and does not absorb water. No separate adhesive is needed. Bonding material is then placed on allpoints of contact between parts, including the outer surfaces of the flanges of the inner hull and/or on the inner surfaces of the flanges of the outer hull and on the upper surfaces of the inner floor. In the case of the model shown, wherein flanges are not provided at the end walls, the abutting surfaces of those walls can be also provided with the bonding material so that, when the structure is assembled and the bonding material is cured, a complete water-tight seal exists around the periphery of the craft.

While one advantageous embodiment has been chosen to illustrate the invention, it will be understood by those skilled in the art that various changes and modifications can be made therein without departing from the scope of the invention as defined in the appended claims.

What is claimed is: l. A boat having an inner hull, an outer hull and an inner floor,

said outer hull having an integrally formed bottom portion and upstanding side and end walls forming a complete, independently floatable shell,

the upper edges of at least said side walls of said outer hull terminating in a continuous laterally extending flange and an upwardly extending short wall at the outer limit of said flange;

said inner hull having an integrally formed bottom portion and upstanding side and end walls forming a complete, independently floatable shell nestable in said outer hull, the contour configuration of said inner hull being substantially identical to that of said outer hull the upper edges of at least said side walls of said inner hull terminating in a continuous laterally extending flange and an upwardly extending short wall at the outer limit of said flange; a rib structure comprising a longitudinal keel member and a plurality of transverse rib members,

said inner floor and said rib structure being disposed in said outer hull portion between the bottom portions of said inner and outer hulls,

said bottom portion of said outer hull being shaped to include a longitudinal cavity to receive said keel member, longitudinal support surfaces for supporting said inner floor, and a cavity therebetween to receive said rib members, and

said laterally extending flange on said inner hull being of significantly greater width than said flange on said outer hull, said flanges being in interfitting mating relationships when said inner hull is fitted into said outer hull with said flange on said inner hull, said side walls of said inner and outer bulls and said inner floor defining a watertight interhull cavity;

flotation material disposed within and substantially filling said cavity; and means for bonding said inner and outer hulls to each other along regions of contact at said flanges, for bonding said inner hull to said inner floor and for bonding said inner floor and said outer hull to said rib structure.

0nd hull at the surfaces which will cooperate in defining the at least one cavity;

applying a curable bonding material to surfaces of the hulls and rib structure which will contact each other in the assembled boat;

assembling the boat; and

simultaneously curing the bonding material in the entire boat. 

1. A boat having an inner hull, an outer hull and an inner floor, said outer hull having an integrally formed bottom portion and upstanding side and end walls forming a complete, independently floatable shell, the upper edges of at least said side walls of said outer hull terminating in a continuous laterally extending flange and an upwardly extending short wall at the outer limit of said flange; said inner hull having an integrally formed bottom portion and upstanding side and end walls forming a complete, independently floatable shell nestable in said outer hull, the contour configuration of said inner hull being substantially identical to that of said outer hull the upper edges of at least said side walls of said inner hull terminating in a continuous laterally extending flange and an upwardly extending short wall at the outer limit of said flange; a rib structure comprising a longitudinal keel member and a plurality of transverse rib members, said inner floor and said rib structure being disposed in said outer hull portion between the bottom portions of said inner and outer hulls, said bottom portion of said outer hull being shaped to include a longitudinal cavity to receive said keel member, longitudinal support surfaces for supporting said inner floor, and a cavity therebetween to receive said rib members, and said laterally extending flange on said inner hull being of significantly greater width than said flange on said outer hull, said flanges being in interfitting mating relationships when said inner hull is fitted into said outer hull with said flange on said inner hull, said side walls of said inner and outer hulls and said inner floor defining a watertight interhull cavity; flotation material disposed within and substantially filling said cavity; and means for bonding said inner and outer hulls to each other along regions of contact at said flanges, for bonding said inner hull to said inner floor and for bonding said inner floor and said outer hull to said rib structure.
 2. A method of making a boat comprising the steps of forming a first inner hull which is independently floatable and which has a laterally extending flange; forming a second outer hull which is independently floatable and is dimensioned and formed to receive the first hull in nesting, interfitting relationship with at least one cavity defined therebetween; forming a rib structure fittable between the hulls; applying a foamable flotation material between the exterior of the first hull and the interior of the second hull at the surfaces which will cooperate in defining the at least one cavity; applying a curable bonding material to surfaces of the hulls and rib structure which will contact each other in the assembled boat; assembling the boat; and simultaneously curing the bonding material in the entire boat. 